Method of removing a backplane from an electrical enclosure

ABSTRACT

An electrical enclosure that includes a sidewall, a back and a top, defining an interior. The top of the enclosure is adapted to open and provide access to the interior. The enclosure includes a backplane mounted to the interior of the enclosure. The backplane has at least one cutout where the cutout is positioned on the backplane to align with an obstacle positioned on the enclosure sidewall and extending into the enclosure interior.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 11/457,287filed Jul. 13, 2006 and claims the priority benefit thereof and ishereby incorporated by reference.

FIELD OF INVENTION

The invention relates to electrical enclosures, and more particularly,electrical enclosures with removable backplanes.

BACKGROUND OF THE INVENTION

Electrical enclosures are cases used to protect the electricalcomponents stored inside the enclosure. The electrical components aremounted on a backplane or backplate (backplane and backplate are usedinterchangeably) or panel that is secured or mounted to the interior ofthe enclosure case. The backplane may be predrilled with a series ofopenings to accommodate electrical components. Typical enclosures arerectangular boxes constructed of metals such as steel, or fiberglass orplastic. The enclosure generally has a top cover or door that can beopened to provide access to the electrical components mounted in thepanel. The cover, when closed, provides a degree of protection for theelectrical components against moisture and other adverse environmentalconditions. Electrical wiring penetrates the enclosure typically throughconduits or similar devices that are secured to the enclosure usingspecialized fittings.

Some enclosures include an inner swing panel or interior cover platethat is exposed when the enclosure cover is opened. The interior coverplate generally is mounted on the enclosure behind the door or enclosurecover. The interior cover plate or inner swing panel is used to mountswitches, circuit breakers, gauges, lamps or other components that theoperator may need to periodically access for various reasons, but stillprotect the electrical components mounted on the backplate. The interiorcover plate can be moved to provide access to the interior of theenclosure. Generally, the inner swing panel is hingedly connected to theenclosure, but can be screw mounted, toggle mounted or otherwiseremovable. An example of such an enclosure is shown in FIG. 1. Shown areenclosure 1, cover 2, and interior swing panel 3. The interior swingpanel 3 shown in FIG. 1 is hingedly mounted to the enclosure, as is thecover plate 2. To accommodate a hingedly mounted interior swing panel,many enclosures include an interior projection support bracket attachedto the interior of the enclosure opposite the hinged side of theinterior swing panel (not shown). This bracket is used to support theinterior swing panel in a closed position.

In assembling an enclosure, the electrical components will be installedand wired as needed to the backplane. The backplane is then insertedinto the interior of the enclosure and secured to the enclosure(usually, by corner screw mounts installed at suitable locations in theinterior of the enclosure). The door components are added (either to theinterior cover plate, inner swing panel or enclosure cover or both) aswell as components mounted in the exterior of the enclosure (such aswarning lamps, alarms or lightning arresters), and wired to thebackplane as needed. The assembled enclosure is then transported to thefield, where suitable enclosure cutouts are installed through theenclosure to accommodate the incoming conduits or other devices. In someinstances the enclosure cutouts can be placed in the device in theassembly plant, if a high degree of tolerance is expected in the fieldinstallation.

The assembled enclosure is then mounted at its desired location, andconduits attached, providing power and control wiring to enter or exitthe interior of the enclosure. Once the enclosure is assembled, mountedand conduits attached, removal of the outer enclosure is difficult, asthe conduit must be disassembled and moved, and this may have to beinitiated at a location remote from the enclosure. Hence, servicing ofcomponents in the enclosure generally entail field service of thecomponents on the backplane while the backplane is installed. Removal ofthe backplane from a fully installed enclosure is very difficult orimpossible. The conduits and other devices that are mounted on theexterior of the enclosure or the inner swing panel have an interiorextent—that is, the conduit or other devices extends into the interiorof the enclosure and presents a physical obstacle to lifting thebackplane off the mounts and out of the interior. The backplane, to beremoved, would require removal of the interior penetrations of theconduit or other exterior mounted devices, that is, a disassembly of thefield mounting of the enclosure. In most cases this is not possiblewithout undesirable lengthy shut down of equipment and excessive costs.

In instances where extensive re-hab of the electrical components arerequired (for instance, due to flooding) or where new designs requirefor extensive replacement of components, a complete new enclosure andbackplane may be required in the field to “swap” out with the existinginstalled enclosure. Such a procedure is expensive and time consuming.It would be beneficial to be able to remove the backplane from theenclosure without disassembling the field mount. While the exteriorelectrical connections to the backplane would have to be broken, theintegrity of the field mounted enclosure would not be broken. Theability to remove the backplane and the attached electrical componentswithout disturbing the enclosure field mount is desirable

SUMMARY OF THE INVENTION

The invention provides for an easily removable backplane. The backplanehas cutouts aligned with the location of elements that protrude into theinterior of the enclosure. This invention combines all interiorcomponents into one “bucket” style module which can be easily removedallowing for complete replacement of the module, leaving the mainenclosure permanently field mounted. The invention will be described inthe context of an enclosure for a sewage lift station, but should not belimited to this particular application.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 is a perspective view of a prior art enclosure.

FIG. 2 is a schematic of a pump station showing the electrical enclosureused in the station

FIG. 3 is a front view of an enclosure showing the backplane installed.

FIG. 4 is a front view of the enclosure of FIG. 3 with componentsmounted on the backplane.

FIG. 5 is a prospective view of the backplane/inner swing panelassembly.

FIG. 6 is an exploded view showing the backplane/inner swing panelassembly and enclosure.

PREFERRED EMBODIMENT OF THE INVENTION

A typical sewage lift station consists of pit, pump, floats for pumpactivation and a control panel. The lift stations can be located inpopulous areas such as subdivisions and are susceptible to tampering orvandalism. This requires that the controls be tamper resistant, andhence all the controls, switches, lights and the like are mounted andsealed in an outer enclosure. The outer enclosure of the control panelmay be made of many materials, including steel, aluminum, plastic orfiberglass. The controls needed to operate the lift station are usuallylocated inside the enclosure mounted on a backplane, typically a plate(not necessarily flat) which may also be made of various materials. Thebackplane may be pre-perforated for mounting typical electricalcomponents. Typically, a specific pump control panel is designed for theapplication, and the design implemented by assembling the neededelectrical components onto the backplane, wired appropriately, and theassembled backplane is then tested in a facility specializing in controlpanel manufacturing prior to field installation.

The sewage lift station control panel consists of an enclosure (shell),an inner backplane and electrical components which are mounted on aninterior cover plate or inner swing panel (not to be mistaken with theouter enclosure door). The enclosure has a sidewall, a back and a top,where the top can be opened to provide access to the enclosure interior.As shown, the top is a cover that is hinged to the sidewall. Theinterior cover plate or inner swing panel door usually contains lights,switches and meters, counters or timers. The outer enclosure has mountedon it various components 10 that penetrate the enclosure, 1 such asalarm lights, lightning arrestors, and conduit penetrations thatprotrude into the enclosure, as shown in FIG. 3. These interiorprotrusions restrict the removal of an installed backplane 5. Periodicrepair and upgrade of controls is commonly performed on sewage liftstations, in which case, the entire control panel, enclosure and allinternal components must be removed from its mounted field location andsent back to the factory for upgrade or repair or removed and replacedwith a new enclosure (to minimize down time). To enable the backplane tobe removed as a module (removal of all components mounted on thebackplane), the backplane will have notches or cut-outs 20 in thebackplane that are substantially aligned with components 10 mounted onthe enclosure, to allow the backplane 5 to be lifted out of theenclosure 1, providing the needed clearance past those componentsmounted on the enclosure that penetrate into the interior. See FIGS. 3and 4. As can be seen in FIGS. 3 and 4, the number of cutouts 20 can beless than the number of obstructions 10, as a single cutout 20 canaccommodate a number of obstructions 10. For instance, the bottombackplane cutout of FIGS. 3 and 4 accommodates four conduit attachments.Alternatively, the backplane 5 may have a hinged portion or a detachableportion that can be removed or rotated up and out of the way to providethe needed clearance over obstructions in the enclosure's interior (notshown).

Shown in FIG. 4 is the backplane with installed components positioned onthe backplane 5 in the interior of the enclosure 1. The backplane orplate is mounted to the interior of the enclosure 1, generally by boltsthrough openings 30 on backplane into an aligned bolt mount positionedon the enclosure interior. To remove the backplane and mountedcomponents, the wiring on those devices 10 that connected to thebackplane must be disconnected. After disconnection, the bolts holdingthe backplane to the enclosure are removed, and the entire backplanemodule (backplane+installed components) can be easily removed withoutdisassembly of the filed installation of the enclosure itself.

As mentioned above, the enclosure may include two covers, an exteriorcover and an interior cover. The interior cover may have devices mountedon the interior cover, but these devices would not be mounted onto theexterior cover. In this instance, it may be desirable to remove thebackplane and interior cover at the same time. In this instance, theinterior cover should be attached to the backplane to allow the assemblyto be extracted as a unit. Such an assembly is shown in FIG. 5. Shown isbackplane 5, with cover support 12, shown as upstanding legs 12 a. Theinterior cover 3 is attached to one pair of legs. Obviously, instead ofa pair of legs, a cover support 12 c (shown as dashed in FIG. 5) couldbe used.

As shown in FIG. 5, the interior cover plate is an inner swing panel 3that is hingedly attached to the cover support 12. Instead of beinghingedly attached, the interior cover plate could be attached to thelegs by screws, bolts, latches or other attachment means. As shown inFIG. 5, one pair of legs is used to attach the inner swing panel 3 tothe cover support 12, and the opposing pair of upstanding legs 12 isused to support the swing panel 3 when closed. In this embodiment, innerswing panel 3 has latches 4 that interface with a horizontal tab 12 bpositioned on the cover support to allow the interior cover to latch. Insome installations, the opposing support legs may not be required, asthe interior cover, if suitably sized, could rest on a lip formed by theenclosure. Instead of upstanding legs 12, upstanding posts 12 a could beused, as shown by the dashed posts in FIG. 5. These posts could bescrewed to or bolted to the backplane.

FIG. 6 shows how the backplane 5 is removably inserted into theenclosure. Also shown in FIG. 6 is a raised platform 40 mounted on thebackplane. Such a raised platform is used to mount switches and lightsand other devices when there is no inner swing panel for mounting. Toassist in removal, the backplane (or inner swing panel) can be equippedwith handles or grab bars. The invention, as described, provides a onepiece module that allows a factory to build a new module and ship it tothe lift station in need of repair or upgrade. The old module would thenbe removed from the existing enclosure and the new module installedquickly and easily. This insures the lift station is non operational foronly a short period of time. The invention allows the control panelmanufacturer to have a set of standardized modules so as to allow a“module only” assembled backplane to be shipped in the event of rehab orreplacement of an existing module.

1. A method of removing a backplane from an installed electricalenclosure, where said electrical enclosure comprises a sidewall, a backand a top, defining an interior, said top adapted to open and provideaccess to said interior, a plurality of components positioned on saidenclosure and projecting into said interior of said enclosure (forming“interior projections); said plurality of components including at leastone conduit coupled to said sidewall, wiring passing though said conduitinto said interior of said enclosure; a backplane mounted in theinterior of said enclosure and having a series of electrical devicesmounted on said backplane, said backplane having at least one cutout, atleast one of said interior projections being aligned with one of said atleast one cutout, said wiring coupled to a subset of said electricaldevices; said backplane further comprises an upstanding leg and aninterior cover plate coupled to said upstanding leg wherein saidinterior cover plate is hingedly mounted to said upstanding leg; themethod comprising the steps of decoupling said wiring from saidelectrical devices; dismounting said backplane from said enclosure; andremoving said backplane from said enclosure interior without decouplingsaid conduit from said enclosure.
 2. The method of claim 1 wherein saidsidewall comprises a left exterior sidewall, a right exterior sidewall,a top exterior sidewall and a bottom exterior sidewall.
 3. The method ofclaim 1 wherein said backplane includes a handle or grab bar, and saidstep removing said backplane further comprises the step using saidhandle or said grab bar to remove said backplane.
 4. A method ofremoving a backplane in a combination of an installed electricalenclosure comprising an enclosure having an exterior sidewall, a backand a top, defining a substantially closed interior, said top adapted toopen and provide access to said interior, a plurality of componentspositioned on said enclosure exterior sidewall and projecting into saidinterior of said enclosure, one of said components comprising a conduit;a removable backplane comprising a backplane mounted to the interior ofsaid enclosure, said backplane having at least one upstanding leg,wherein said interior cover plate is hingedly connected to one of saidat least one upstanding legs said backplane having a cutout, at leastone of said interior projections of said components being aligned withsaid cutout, where said cutout is sized to allow said backplane to beremoved from said interior of said enclosure without decoupling saidcomponents positioned on said enclosure exterior sidewall that arealigned with said cutout, said method comprising the steps of decouplingsaid wiring from said electrical devices; dismounting said backplanefrom said enclosure, and removing said backplane from said enclosureinterior without decoupling said components aligned with said cutout. 5.The method of claim 4 wherein said components comprise warning lamps,lighting arrestors, or electrical conduits, or conduit connections or acombination thereof.
 6. A method of removing a backplane from aninstalled electrical enclosure, where said electrical enclosurecomprises a sidewall, a back and a top, defining an interior, said topadapted to open and provide access to said interior, a plurality ofcomponents positioned on said enclosure and projecting into saidinterior of said enclosure (forming “interior projections) wherein asubset of said components extends through said sidewall; said pluralityof components including at least one conduit coupled to said sidewall,wiring passing though said conduit into said interior of said enclosure;a backplane mounted in the interior of said enclosure and having aseries of electrical devices mounted on said backplane, said backplanehaving at least one cutout, at least one of said interior projectionsbeing aligned with one of said at least one cutout, said wiring coupledto a subset of said electrical devices; the method comprising the stepsof decoupling said wiring from said electrical devices; dismounting saidbackplane from said enclosure; and removing said backplane from saidenclosure interior without decoupling said conduit from said enclosure.